i) Field of the Invention
The present invention relates to a thermal head, and more particularly to a thermal head for a low voltage drive, and an electronic apparatus such as a printer, a word processor, a facsimile machine, a plotter or the like using the thermal head.
ii) Description of the Related Arts
Generally, in a thermal head, a common electrode conductor and separate electrode conductors are formed on an insulating substrate, and a plurality of heating resistors are connected to the common electrode conductor and the separate electrode conductors. Further, semiconductor driver IC elements for separately driving the heating resistors are also formed on the substrate. In the thermal head of this kind, conventionally, two power source systems to supply 5 V for driving a logical system and 12 to 24 V for driving heating resistors are provided.
In this conventional thermal head, usually, since two power source systems are used, the size of the thermal head is enlarged and its fabrication cost is increased. Also, it is difficult to carry out battery driving. Further, in another conventional thermal head in which low voltage driving is enabled by varying the resistance values, an output saturation voltage of the semiconductor driver IC elements is large and printing efficiency is low. Hence, life of a cell is short and the recording speed can not be raised.